One of the breakthroughs in security associated with retail merchandizing has been the advent of electromagnetically responsive tag systems. Today, these are used in clothing stores, libraries, and book stores. The overall topology involves a tag which is responsive to electromagnetic energy and which will trigger an alarm system if a patron attempts to leave with the item without having the item tag disabled from tripping the alarm. For books and other devices presenting the opportunity to have the device hidden, thefts have been deterred significantly. The dishonest patron has only a small chance of finding the device, and still cannot be certain if there might be another located on the book. Therefore as to books and the like, the currently used systems have proven effective.
With clothing, there are still practical problems involved. It is difficult to effectively hide the electromagnetically activated tags commonly available on clothing. If sewn into the clothing, such tags would be difficult to physically remove without having to rip clothing seams. When attached to the outside of clothing, they may be found and easily removed by thieves.
As a result, the technology of the past few years has emphasized the mechanical nature of these tags. Elaborate tags have been designed which cause a small nail sized pin to pierce the clothing from one side and be secured on the other side to a pivotal piece of the tag. The locking mechanism is a mechanical lock on the pin, either through friction, or into a groove cut in the pin or nail. The problems with this arrangement is that the pin or nail can significantly destructively effect the clothing upon which it is mounted. Where the pin or nail is made of a rustable metal, moisture can cause rust to be formed along the shaft, which may wick into the clothing material. Not only can discoloration occur, but the rust can chemically destroy the clothing.
It was discovered that by placing pressure on the unlock mechanism, a thief can open these devices. Since the thief's unlocking pressure tended to be less evenly distributed than the tool intended to unlock the tag, the inventors went a step farther and placed vials of dye in the clothing tag to further stain and ruin the clothing on the theory that having the clothing ruined is better than having it stolen.
The engineering techniques employed in tagging systems are known, and the following examples are incorporated by reference herein. U.S. Pat. No. 5,280,159 issued to Schultz et al. on Jan. 18, 1994 and entitled MAGNETIC RADIO FREQUENCY TAG READER FOR USE WITH A HAND-HELD TERMINAL discloses a gun-style reader which reads information from a tag when the tag is exposed to a low frequency magnetic field. U.S. Pat. No. 5,241,163 issued to Vachtsevanos et al. on Aug. 31, 1993 and entitled ARTICLE IDENTIFICATION APPARATUS AND METHOD USING A FERROMAGNETIC TAG discloses the use of magnetic bars and non-magnetic strips which can be read as a bar code.
U.S. Pat. No. 5,182,544 issued to Aquilera et al. on Jan. 26, 1993 and entitled SECURITY TAG WITH ELECTROSTATIC PROTECTION discloses the use of flat formed capacitors and inductors on a tag, and emphasizes the use of a static dissipation member. The scheme discloses a frangible connection between the plates of capacitors C2 and C4. Where the preferred frequency is 8.2 MHz for the tag security system, the frangible connection is set to cause the tag frequency to be 16 MHz. When the tag is exposed to sufficiently high levels of 16 MHz energy, the frangible connection burns out, leaving a circuit intact which now operates at 8.2 MHz. The problem here is not knowing whether you have actually altered the resonant frequency of each tag except by testing it, and especially where the application of the burnout energy may be dependent upon the orientation and momentary field strength of the applied field. Where the burnout fails, the tag will fail to trigger in the alarm system, and goods bearing the tags may be easily stolen. Further, there is no affirmative way of knowing whether the tags are in a triggering or non-triggering condition based upon inspection.
U.S. Pat. No. 5,170,045 issued to Bengtsson on Dec. 8, 1992 and was entitled PRICE TAG DEACTIVATOR, discloses rows of alternately polarized magnets, used with magnetic strips on bar code price tags to alarm when the price is not scanned, and includes the banks of magnets incorporated with the scanning system to automatically demagnetize during scanning.
U.S. Pat. No. 5,103,210 issued to Rode et al. issued on Apr. 7, 1992 and entitle ACTIVATABLE/DEACTIVATABLE SECURITY TAG FOR USE WITH AN ELECTRONIC SECURITY SYSTEM discloses a tag activate by changing the resonating frequency to a second resonating frequency by again exposing the tag to electromagnetic frequency to burn out or alter the circuit. This scheme also suffers from the limitations outlined above for the U.S. Pat. No. 5,182,544.
U.S. Pat. No. 5,081,446 issued to Gill et al. on Jan. 14, 1992 and entitled SECURITY TAG FOR COMPACT DISC STORAGE CONTAINER discloses the formation of a circuit whose frequency is formed by interaction between a compact disc and the casing. U.S. Pat. No. 5,049,856 issued to Crossfield on Sep. 17, 1991 and entitled ANTIPILFERAGE SYSTEMS, discloses spiral wound emitter and detector coils for use with tags to make a tag less orientationally dependent in detection of the tag's signal.
U.S. Pat. No. 4,999,609 issued to Crossfield on Mar. 12, 1991 and entitled ANTIPILFERAGE TAGS HAVING AN ACOUSTIC RESONATOR CHAMBER discloses a three dimensional structure having a magnetorestrictive material where the alarm tone comes directly from the tag's acoustic resonator chamber. U.S. Pat. No. 4,992,776 issued to Crossfield on Feb. 12, 1991 and entitled ANTIPILFERAGE TAGS AND THEIR USE discloses a system to work with the magnetorestrictive material in a tag.
U.S. Pat. No. 4,567,473 issued to Lichtblau on Jan. 28, 1986 and entitled RESONANT TAG AND DEACTIVATOR FOR USE IN AN ELECTRONIC SECURITY SYSTEM which again discloses the use of resonance to cause conductive failure, in this case by vaporization, to destroy the resonant nature of the circuit. Again and depending upon the user's ability to see the circuitry, the tag's disablement may not be immediately discernible. This is a disadvantage, since the purpose of the tag is that it be non-detectable by users as having a circuit or security function.
U.S. Pat. No. 4,168,496 issued to Lichtblau Sep. 18, 1979 and entitled QUASI-STATIONARY NOISE CANCELLATION SYSTEM, illustrates a circuit for cancelling spurious resonance in a detection system. U.S. Pat. No. 4,117,466 issued to Lichtblau Sep. 26, 1978 and BEAT FREQUENCY INTERFERENCE REJECTION CIRCUIT, illustrates a circuit for rejecting beat frequency in detection systems.
U.S. Pat. No. 84,021,705 issued to Lichtblau on May 3, 1977 and entitled RESONANT TAG CIRCUITS HAVING ONE OR MORE FUSIBLE LINKS discloses a circuit on a substrate which is fusible to destroy the link to open circuit by introduction of electromagnetic energy. U.S. Pat. No. 3,967,161 issued to Lichtblau on Jun. 29, 1976 and entitled MULTI-FREQUENCY RESONANT TAG CIRCUIT FOR USE WITH AN ELECTRONIC SECURITY SYSTEM HAVING IMPROVED NOISE DISCRIMINATION discloses the use of multiple frequencies as a spread spectrum method of improving noise rejection.
U.S. Pat. No. 3,913,219 issued to Lichtblau on Oct. 21, 1975 and entitled PLANAR CIRCUIT FABRICATION PROCESS discloses fabrication of planar electrical circuits having precision electrical characteristics, and includes materials such as polyethylene, polypropylene, Teflon based materials, and polyisobutylene, as well as the use of nitrocellulose inks. The method of interconnecting two sides of the circuit is not disclosed.
U.S. Pat. No. 3,863,244 issued to Jan. 28, 1975 and entitled ELECTRONIC SECURITY SYSTEM HAVING IMPROVED NOISE DISCRIMINATION discloses the use of a first circuit for detection and a second circuit to permit partial destruction of the first circuit to change it resonant frequency. U.S. Pat. No. 3,828,337 issued to Lichtblau on Aug. 6, 1974 and entitled NOISE REJECTION CIRCUITRY discloses circuitry for rejecting unintended pulses, by using a parallel noise inhibit function.
U.S. Pat. No. 3,810,147 issued to Lichtblau on May 7, 1974 and entitled ELECTRONIC SECURITY SYSTEM discloses the use of fusible ink in a tag in a system in which a continuous series of frequencies are swept, and which can be de-activated by a de-activation frequency. U.S. Pat. No. 3,292,080 issued to E. M. Trikilis on Dec. 13, 1966 and entitled SYSTEM AND METHOD FOR PREVENTING PILFERAGE BY DETECTION OF MAGNETIC FIELDS uses raw flux density as a qualifier to perform sensing.